docs: def load_model(path):
      """Load a model from a pickle file in the data directory. Cached so model is only loaded once."""
      abspath = find_data(path)
      cached = _model_cache.get(abspath)
      if cached is not None:
          log.debug('Using cached copy of %s' % path)
          return cached
      log.debug('Loading model %s' % path)
      try:
          with io.open(abspath, 'rb') as f:
              model = six.moves.cPickle.load(f)
      except IOError:
          raise ModelNotFoundError('Could not load %s. Have you run `cde data download`?' % path)
      _model_cache[abspath] = model
      return model